Hemostatic Disorders and Coagulation Test Abnormalities

Prolonged activated partial thromboplastin time (aPTT)

  No clinical bleeding – factors XII, high-molecular-weight kininogen, protein kinase
  Variable, but usually mild, bleeding – factor XI, mild FVIII and FIX
  Frequent, severe bleeding – severe deficiencies of FVIII and FIX
  Heparin


Prolonged prothrombin time (PT)

  Factor VII deficiency
  Vitamin K deficiency – early
  Warfarin anticoagulation


Prolonged aPTT and PT

  Factor II, V or X deficiency
  Vitamin K deficiency – late
  Direct thrombin inhibitors


Prolonged thrombin time

  Heparin or heparin-like inhibitors
  Mild or no bleeding – dysfibrinogenemia
  Frequent, severe bleeding – afibrinogenemia


Prolonged PT and/or aPTT not correct with mixing with normal plasma

  Bleeding – specific factor inhibitor
  No symptoms, or clotting and/or pregnancy loss – lupus anticoagulant
  Disseminated intravascular coagulation
  Heparin or direct thrombin inhibitor


Abnormal clot solubility

  Factor XIII deficiency
  Inhibitors or defective cross-linking


Rapid clot lysis

  Deficiency of 2-antiplasmin or plasminogen activator inhibitor 1
  Treatment with fibrinolytic therapy